My best friend has called me Kae Kae since we were very little, though my name is Karin. Now I use Kae Kae a lot, though I don't ask my teachers to call me that, but I wish I did. I don't really like just Kae. I think two Kaes sound better. I don't think this is good as a full name. Kay would be better (my same best friend's mom is named this).
This is my nickname (my given name being Kelsey). I picked it because I dislike the other nicknames that go with Kelsey (i.e. Kel, Kels). I get a lot of compliments, saying that both the sound and the spelling are unique and quite pretty.